Ortho-(hydrocarbylthio)phenols are useful compounds, e.g., as intermediates in the preparation of hypotensive drugs and agricultural chemicals such as plant protection agents, herbicides, pesticides and the like. U.S. Pat. No. 2,923,743 describes a process for the production of aryl-alkyl thioethers by reacting a dialkyl disulfide with aromatic compounds such as phenol, chlorophenol, p-cresol, 2-naphthol, etc., in the presence of suitable condensation agents, such as for example, aluminum chloride, aluminum bromide, ferric chloride, zinc chloride, tin tetrachloride, antimony pentachloride, boron fluoride and bleaching earth. At Column 1, lines 31-36, that patent discloses:
"These condensation agents can be added in different amounts. In general there should be added at least molecular amounts referred to the dialkyl disulfide but there can be used also higher amounts e.g. a 3-fold surplus of the condensation agent."
U.S. Pat. No. 3,246,040 discloses the synthesis of certain substituted phenolic compounds containing two alkylthio groups and from 0 to 3 halo or nitro groups. This patent discloses that the compounds are useful as pesticides; as inhibitors of the germination of fungus spores, they are effective fungistats. They are also useful as intermediates in the preparation of biologically active materials such as organic phosphates.
In our U.S. Pat. No. 4,324,920, the disclosure of which is incorporated herein by reference, we disclose a process for the preparation of ortho-(hydrocarbylthio)phenols by contacting phenols, having at least one hydrogen on a carbon atom ortho to a hydroxy group, with hydrocarbyl disulfides in the presence of catalytic amounts of aluminum phenoxide.